Key changers, MP3, Wav, etc. software versions especially. Does anyone have any working experience with them?

1. Do any of them actually work, without coloring the sound to the point where it is nearly unusable?

2. Do the karaoke machines, ie; vocopro, singing machine etc, do any better job than the software PC versions?

The ultimate goal is to occasionally use prerecorded karaoke tracks to do a quick set. If I build the songs in RB, it takes awhile and getting all the instrumentation is sometimes a problem to do it well, such as a signature Pedal Steel Solo. Real Track PSG is great for what it can do, but it does have it's limitations.

If I buy a CD+G, or an MP3+G that sounds very close to the original, I may need to move the key up or down one or two steps for my range. Usually this results in artifacts, coloration, or major pollution to the track, making it unusuable, which forces me to do my own arrangement that may lack some of the signature elements.

Any ideas?

Dang....This is addicting.

http://www.reverbnation.com/roberttrippmusic